Pouring on the Power

Yeti Factory Racing rider Jared Graves, who got started racing BMX bikes and now sits third in the World Enduro Series, says that he is addicted to training with power.

Road racers have been using power meters to guide their training and racing for more than a decade, measuring the watts they produce on everything from recovery spins to day-long breakaways. Mountain bikers, aside from some cross-country and endurance racers, have been slower to incorporate the tool into their training.

Riders have been turned off by the devices’ additional weight, the lack of compatibility with some drivetrains, the price, and the simple fact that both hub-, and crank-based meters could be susceptible to damage on the trail. Many of those objections are about to fall away, and enduro specialist Jared Graves, third overall in the Enduro World Series, a long-time power meter devotee, is very excited.

“It’s something I first started using during BMX training,” explained the Yeti Factory Team rider, who competed in the 20-inch racing discipline at the 2008 Beijing Olympics. “It was a really helpful way to measure improvement and get an idea of what my weak and strong points were. That got me interested in that specific side of training and I kind of got addicted to it.”

This winter, Graves’ addiction—and that of others like him—found a fix when Stages Cycling launched its new power meter. The device is about the size of a pack of chewing gum, weighs less than 20 grams, and mounts to the inside of the non-drive-side crank-arm, where it’s protected from damage. The meter is covered in Mylar that protects it from water, mud, and dust. A $2 coin cell battery powers the devices, lasts for 200 hours of riding, and is easily replaceable.

Stages’s power meter mounts to the inside of the non-drive crank arm. The device calculates power by measuring deflection (flex) in metal crank arms.

This device calculates power via an array of built-in strain gauges that measure deflection (flex) in the crankarm while you’re pedaling. That data is doubled to account for the other crank arm, and then transmitted via ANT+ or Bluetooth technology to any compatible head unit. Stages also use an accelerometer to provide cadence and speed data.

Initially, Graves says he used the device in a traditional way, cranking out prescribed intensity base miles on his road bike. But the real discovery came when he mounted one on his enduro bike and began collecting data during race-pace training efforts.

“I’d be pushing hard on sections that were 3-15 minutes long, and could then go look at the numbers and get a good idea of high-, and low-end power,” he explained. “Then I could structure some of my interval workouts on the road based around those numbers.”

That meant masochistic efforts such as cranking out 1,000 watts for 6 seconds, resting for 9 seconds, and then repeating. Graves says his new, more analytical approach also produced psychological benefits.

“When you’re training and see your power numbers going up, it becomes a mental advantage going into a race,” he said. “You just feel like you are doing things a bit more proper, not just going out for a regular ride. And that knowledge is key. When I have the bike at 100 percent, the body at 100 percent, then I know I’m ready. That’s huge at this level because everyone has the skills and fitness. You need to believe.”

One reason mountain bike racers have abstained from training with power is the devices’ vulnerability to damage. The svelte Stages unit is well protected, and insulated from the elements.

If Graves is a full-fledged believer, then call Fabien Barel curious. The former world downhill champ, who’s now racing enduro full time, says he’s never used one, but that his coach has been imploring him to get it a try.

“I think that as we have seen here there is a lot of pressure from enduro racing to be in very good physical shape,” said Barel after finishing third at the fourth stop of the Enduro World Series in Winter Park Colorado, where there was a significant amount of pedaling on flat trails. “You see Jared and (overall series leader) Jerome (Clementz) being way ahead of everyone as the two strongest guys because of the shape they are in. To do that you need to have the proper training and the power meter is the future.”

“When I was racing downhill my eyes were closed to these kinds of things,” added Barel. “But now coming into enduro, I see a lot of training strategy coming in from road and cross-country and I think it can bring a benefit to the sport.”

Of course, not everyone is jumping on the power meter bandwagon. Former top-level cross-country pros Adam Craig and Jeremy Horgan-Kobelski have no interest in using the devices in their second careers as enduro racers.

“I never even used one for cross-country, so I’m definitely not using one for enduro,” said Horgan-Kobelski, who was 20th at Winter Park. “But that’s just me. Clearly some people will like to see those numbers. For me, I burned out on the numbers thing a long time ago.”

“I begrudgingly used a power meter when I had to get one percent more fit racing cross country,” said Craig, who was eighth at Winter Park. “But there are a lot of people coming into enduro who might want to use one as a means to get more fit. This sport is like everything else, you need more threshold power and you need more explosive power. I do think there is some interesting data to be collected.”

In Winter Park, Stages introduced its mountain bike power meters, which cost as little as $700, but work only with aluminum cranks.

Not surprisingly, Stages is hoping to capitalize on this interest in data, and launched a mountain bike version of their power meter last month at Winter Park.

“We really feel like there is a lot of value in understanding what you are doing in a race,” said Stages marketing man Matt Pacocha. “Obviously you can’t stare at your power numbers when you are in the middle of an enduro race run. But being able to analyze the data afterward, and then build training plans and get feedback when doing that training can be incredibly valuable.”

It’s also a relatively good value, with devices costing as little as $700 for a SRAM X9 crank, to $900 for Shimano Saint. Keep in mind, though; that price is only for a left-side crankarm—the company does not mount their devices on your crank arm.

Still, that price is less than half the cost of top-end mountain bike products from Quarq and SRM. The new road-only Garmin Vector costs $1,700. PowerTap’s recently price-reduced G3 hub costs $790, still a more expensive option.

One downfall of the Stages model, though, is that it only works with alloy cranks, which bend uniformly. Lighter carbon cranks, on the other hand, bend unevenly, and therefore do not work with Stages’ method of power measurement. But that’s not a problem for Graves. “I don’t weigh my bike,” he said. “I just run what I need to run.”

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